I didn’t see that 50% claim anywhere in that article. Not saying it’s bunk, just that it doesn’t tell us much, especially since different ages react differently. Other countries that are recommending longer spacing seem to think, especially for kids, the data we have now supports 8-12 weeks between shots. Sadly, I don’t think many parents here are aware of that.
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I cant read that link, so I dont know what it says. But I was simply referring to the initial efficacy data, where they said “XX% effective two weeks after first shot, 95% after second shot”. The lower first number is because that many people’s immune system didnt figure it out after the first shot. It isnt about age, it’s a variable on an inidividual level.
I dont know that there is data supporting 8-12 weeks for the initial doses; once the initial dose fades away after ~2 weeks, there’s no reason to wait any particular length of time for the second dose.
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The initial immune system response to the first dose takes about 2 weeks to start working and providing any protection at all - we saw that in the cumulative case curves in the phase 3 vaccine trials and this is in line with expected scientific understanding.
Then there’s the question of how long to wait to provide the second dose, to remind the immune system that this isn’t a one time thing and that it should generate longer term memory cells for how to make the relevant antibodies. The UK delayed their 2nd doses (due to shortages, trying to get all the elderly one dose at least) and did theirs about 2-3 months later, while the US trials were for 3-4 weeks (in part to accelerate the trial results and immunity if it worked) and we had enough supply most people got them on that quicker schedule. There were some follow up studies and they found better immune responses after the longer period -
ie that long after your 2nd delayed shot (~2-3 month between shots) you have better immunity than long after your 2nd undelayed shot (~3-4 weeks between shots). In between however, when you’ve only had 1 shot, you’re definitely less protected.
There’s some question of how the immune memory cells mature I think, and that takes a little while, and if you challenge the system again in the meanwhile it might disrupt that process somewhat. Don’t quote me on that.
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I’ll try not to repeat what @xerty said because he covered it pretty well, so I’ll just speak in more layman’s terms. In the beginning, there wasn’t much data on how long the vaccine lasted. Everyone hoped it lasted forever, but no one really knew for sure. But they did know you were more protected after a 2nd dose, the trials were based on a 2nd dose after 3 weeks, and they wanted people as protected as possible as fast as possible. Once we found out that the efficacy at preventing infection of the 2nd dose started wearing off as quickly as 3 months, the area under the “prevents infection” curve didn’t look nearly as hot and it made more sense to space out the doses to cover more area. Other countries are realizing this and changing their guidelines. Our medical establishment here has their heads too far up their asses to even contemplate saying we should do something different than what they first told us based on new data.
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But are you “more protected”, or “more likely to be protected”? Because (again, as I understand) your immune system either learns to produce the correct antibodies or it doesn’t. And thus the second shot, to ensure your body figured it out, since a significant percentage of people do not after only one shot - their body may figure out part of the correct response, but not the full response… (After my one shot, I had no antibodies at 2 and 5 weeks, although I won’t vouch for the test’s accuracy)
Delaying the second shot does extend the time where you have peak protection. But that’s only because the second shot is functioning as a booster. If the first shot didn’t get the job done, then delaying the second shot is only delaying being protected.
Or am I way out in the weeds? I’m just saying (or trying to say) that the second shot was/is to increase the effectiveness, not durability. Thus why you need both shots before being considered vaccinated.
My layman’s understanding is not that 50% of people have antibodies after 1 shot, but that 1 shot is about 50% as effective as 2. The first shot is not all or nothing. They didn’t give a 2nd shot just to make sure some people that didn’t get immunity from the first got immunity. They gave a 2nd shot because it boosted immunity nearly double. Sure, there are some people that don’t have immunity after 1 shot. But there are also some people that don’t have immunity after 2 shots. We didn’t force 3 shots on people just because a very small number of people don’t get immunity after 2 shots, but might get it after 3.
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See, this makes no sense to me. The effectiveness is the antibodies. The vaccine isnt giving you antibodies, your body is producing them. Therefore, you either produce them (and are protected) or you do not (and you are not). You cant get “more” immunity. I can only picture the claims of “more immunity” as meaning the first shot protects you if you breathe in the virus spores through your left nostril (but you die if it is breathed in through your right nostril), and “more” immunity from the second shot adds protection to that right nostril too. But it [obviously] doesnt work like that.
Partially protected only makes sense in one of two terms. It’s the statistical odds that you are one of the protected in a large group (where “50% protected” means half are and half arent). Or that your immune system worked through 50% of the solution to find the correct antibodies to kill the virus, in which case you still need more exposure for it to complete the puzzle. Either way, that second shot is to improve that percentage, not merely add durability, and any delay only hangs those on the unfortunate side of the equation out to dry.
Right, there was a big jump in success from one shot to two shots, but given the high efficacy of 2 shots there could only be very marginal gains from a third shot no matter how many outliers it might capture. That why the second shot is so close to the first, it’s capturing those who werent successful after the first shot.
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Oh ok. I see what you are saying. But I’m not exactly sure why you believe this is how it works considering the past 10 months. The 2nd shot doesn’t give you “more” immunity. It improves your immune response. And immunity wears off over time. It doesn’t shut off like a faucet after 90 days. So the “you either produce them or you don’t” isn’t an accurate description. That’s why you are more likely to become infected on day 100 vs. day 50. And even more likely on day 150. Just because your body produces antibodies doesn’t mean the antibodies are as effective over time. They don’t just disappear on day 60 for person A and disappear on day 120 for person B, and therefore are statistically gone for everyone on day 90. The effectiveness of the antibodies decrease over time for everyone at similar rates even though you still have them.
Except is does shut off like a faucet. When it deems the threat to be gone, your immune system stops producing the antibodies. Yes, then it takes some time for them to disappear from your system, which is the time factor you are referring to, but that’s a residual effect of “turning off the faucet”. When exposed again, maybe there’s enough residual antibodies lingering around to ward it off, maybe there isnt - but the body recognizes the virus and resumes the production of the appropriate antibodies regardless. That’s what the booster shots accomplish, to replenish those antibodies in anticipation of an immediate threat.
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I think you have the wrong model for the immune system and the vaccines in several ways, glitch.
Firstly, there are several aspects to your immune system, including antibodies, T cells, and NK cells. The latter aspects of the “innate immune system”, while antibodies are the “adaptive” part that are specifically tailored to a particular target.
https://www.khanacademy.org/test-prep/mcat/organ-systems/the-immune-system/a/innate-immunity
Or if you’d rather watch an anime version, this one is fun and quite accurate, showing various invaders and personalized cells in the body coordinating their responses.
Cells at Work! - Wikipedia!
https://www.netflix.com/title/81028791
So you have a first line of defense in the innate immune response, some of which also remembers and can act more quickly. Then you have the adaptive immune response where you make antibodies and possibly remember how if more are needed later. However, antibody production is expensive and you don’t want lots of antibodies running around to things that aren’t threats, partly because of efficiency and partly because they can rarely interact badly ie autoimmune issues, so they’re more on a “just in time” model. after being made, they last 3 months or so, and then degrade.
You cant get “more” immunity. I can only picture the claims of “more immunity” as meaning the first shot protects you if you breathe in the virus spores through your left nostril (but you die if it is breathed in through your right nostril), and “more” immunity from the second shot adds protection to that right nostril too. But it [obviously] doesnt work like that.
Yeah, nothing like that. After an infection, your immune system will have grabbed lots of the foreign pieces it finds and give them to the adaptive immune system (B cells) and they will try to make a range of antibodies against them. However, not all pieces that you find of the virus are useful to make antibodies against - there are “neutralizing antibodies”, which slow or stop the spread of the virus by blocking the spike protein or otherwise tagging the exterior of the virus for immune attack, and there are others such as to the interior which might help clean up the mess later but won’t help stop an active infection at all and may just generate more inflammation in the meanwhile.
There is also a big range of antibodies. Molecular binding is to a very small piece of the virus, so there are 100s of places just on the spike protein that you could try to bind, and some will work better than others both in terms of conformational / electromagnetic binding and usefulness. The guys like Regeneron screen tons of antibodies from survivors or even infected animals for those that bind best and neutralize the virus most successfully in a lab and then brew up lots of these best ones for injection as “monoclonal” treatment (single artificially made antibody).
Partially protected only makes sense in one of two terms. It’s the statistical odds that you are one of the protected in a large group (where “50% protected” means half are and half arent). Or that your immune system worked through 50% of the solution to find the correct antibodies to kill the virus, in which case you still need more exposure for it to complete the puzzle. Either way, that second shot is to improve that percentage, not merely add durability, and any delay only hangs those on the unfortunate side of the equation out to dry.
Firstly, vaccine “efficacy”, as measured against inflection in the trials, is whether you get sick enough to have symptoms, and how many people with the vaccine avoid that on a relative basis compared to the control people without the vaccine. Some people still got sick even with the vaccine, just fewer. That depends on tons of factors, like the specific health and immune response and which antibodies were made and how much virus they got exposed to etc etc. it’s a statistical measure, not really something you can personalize. Also, it’s a relative risk, as in 50% efficacy (which is what the vaccines now seem to provide vs noticeable infection say 6+ months after the last shot) means that if you were exposed to the same situation that would cause an unvaccinated person to get sick, you’d have a 50/50 chance of avoiding that. It’s not that half the people failed to have an immune response and are 100% vulnerable and the other half are 0% vulnerable. Nearly everyone generated antibodies, some better than others, and whether you get symptoms is more of a race between the virus replication and your immune system ramping up and trying to stop it than that you’re 100% protected somehow. Delta is faster so it wins the race more than the Wuhan Classic, which is part of why the vaccines stopped symptoms better before than they do now. Also, of course if your antibodies are still around and on high alert, that helps a lot than only making them 2 days later after the virus is reproducing exponentially, especially if it was a large exposure.
Secondly, my understanding is the main point of the second shot is not to improve protection as much as to remind your adaptive immune system that this should be treated as an ongoing threat. If it’s a one time thing, your body beats it and then forgets about it, more or less. But if it comes back again within a relatively short period of time, then this triggers the creation of long term memory cells, and this is the main point of the vaccine - to trigger that memory so you’ll still be able to generate a good immune response if you don’t otherwise get exposed to covid in the next 3-4 months post-vaccine (which would similarly serve as a reminder to your immune system of the ongoing threat). Much more in this general article -
Right, there was a big jump in success from one shot to two shots, but given the high efficacy of 2 shots there could only be very marginal gains from a third shot no matter how many outliers it might capture. That why the second shot is so close to the first, it’s capturing those who werent successful after the first shot.
Yes, there are a few people where their immune system doesn’t work well and maybe one or even two vaccine shots “don’t take”. This is why the 3rd booster was initially recommended for the elderly and immunocompromised - not just because they are more at risk of bad outcomes, but because their immune systems are less good and might need additional exposure to get a decent response.
Everyone is different. I know a healthy person who was getting some required vaccine for healthcare work pre-covid and they have a test to see if your body generated the immune response to the vaccine. And theirs didn’t, even after getting multiple rounds of the vaccine. They just had a super aggressive innate response that dealt with the problem quickly (really painful injection site after the vaccine) but then didn’t trigger the memory aspect. Eventually their work decided they’d be fine against this particular disease since apparently it was getting cleared quickly by some other part of their immune system and that was good enough.
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Xerty - I dont see how anything you wrote disputes my understanding? I agree with all of it, you’ve just dove into it with much more detail.
If that were the case, then the efficacy wouldnt go up [significantly] after the second shot, and you would be considered vaccinated after the first shot. The efficacy goes up with the second shot because it helps produce a better response, thus better protection. Sure, it also extends the “best” protection a couple weeks, but that’s just a function of time and is tangent to the primary purpose of the second shot. There’s a reason it requires two shots (plus two weeks after the second shot) to be considered vaccinated in the first place, instead of the second shot merely being considered a booster to the initial vaccine.
A booster shot is not intended to improve your protection (although it does in some outliers who’s immune system still couldnt figure out the solution after two shots), it reinforces the ongoing urgency of an immediate response and restores the initial level of protection provided by the first two shots. Yes, the second shot is essentially a booster for those for whom the first shot produced a successful response, just like the first shot is more of a booster for those who have previously recovered from an infection. But delaying the second shot (what started this discussion) would only delay protection for those for whom the first shot did not produce a successful response.
I do agree that there’s a level of memory that is also triggered by multiple exposures, so there is a secondary benefit to getting the second shot before your immune system has forgotten the response to the first exposure. But it clearly isnt essential to memory in general, since one of the vaccines does only require one dose. Regardless, even if so, delaying the second shot to 3-4 months only increases the number of people who’s immune system will have forgotten the response before the second exposure. Two shots 3 months apart would, in general, be far more efficient than 2 shots then a booster 3 months later, but it also would leave lots of gaps and holes big enough to drive truckloads of stock options through.
My general takeaway is, that if we need to put so much effort into convincing our immune system how much of a threat this virus is, then maybe we should reevaluate how much of a threat this virus really is? I’m pretty sure that a better diet and a little exercise would be pretty effective at preventing serious illness from covid in most people, too.
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Well i haven’t seen stats for how well JNJ lasts vs the two dose ones, say 1 year post vaccination, but I wouldn’t at all be surprised if it was a bigger decline (even from the lower initial baseline).
The original two dose trial was because the vaccine manufacturers weren’t sure they would work and hoped a second one would help get it over 50% efficacy which was the FDA’s target for approval. Needless to say many of these were a lot better than people expected.
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All the recent data on this says that 8-12 weeks between shot 1 and shot 2 is better long term for the general population, and especially kids, than the original 3 weeks. You can argue your logic all you want and claim it is in line what what @xerty described, but the data doesn’t support it. I don’t blame the ‘very smart people’ setting policy for wrongly picking 3 weeks as the timeline a year ago. But I do blame them for sticking with it now when we have new data that doesn’t support that timeline.
You get no argument from me on this point.
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I think you are missing my point. Pfizer’s clinical data showed protection between the first and second shot to be just over 50% (which upon further review may have been understated, but is the entire reason for there being a second shot). Of course spreading out the doses may be more effective long term, but it also means leaving nearly half unprotected for a longer time before getting the second dose. Defeating the whole reason for it’s emergency use.
A booster is for long term durability. The second shot is not a booster. It sounds like you are more arguing that there is no need for the vaccine to be a 2-dose regiment, just one shot then a booster later on. Which Xerty also seems to imply in his last comment, and may be true (thus the truckloads of stock options comment).
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I’m arguing that since covid isn’t something we can vaccinate our way out of, the better long term vaccine schedule is to spread out the two shots. Look at it like a graph with the area under the lines being the amount of immunity one has.
Right. You’re extending the effectiveness of the second shot, to the detriment of the immediate protection level. I understood what you were saying.
The only reason there are two shots 3 weeks apart is because that top graph was deemed not high enough. Until you debunk that premise, none of the rest is relevant. You are arguing that it should be a one-dose vaccine, with boosters over time; that the contrary to the official conclusions, the light blue is good enough protection. You get the extended timeframe with the third “booster” shot, meaning you want to just skip the second shot as part of being considered vaccinated.
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No, @xerty went over the main reasons already.
Since the premise is false, I don’t have to debunk it. Regardless, even if the premise were true, the new data WOULD debunk it.
The point is, new data tells us how quickly the graph drops off and that new data should be factored into the decision on how long in between shots. Back when they picked 3 weeks, they didn’t know, they didn’t have the data we have now. Places where the public health officials don’t have their heads as far up their asses are changing the timeline because it makes sense to with the new data.
This is semantics. I’m not arguing for or against 1, 2, 3, or 15 doses. I’m arguing (mainly) that it would be nice if the public health officials in this country did the right thing more often - specifically in this case - changes the timeline between doses.
I’ll admit I only glanced over the long discussion above, but I didn’t see any actual references to this. Can we please get some links to where and how the timelines were changed?
What data? Because from the trials on, there havent been 1-dose test subjects, in a trial or (in any critical mass) in the field. I dont disagree that the longer the time between shots, the longer the protection will last - that’s why they want additional boosters over time. But is there any data that one shot is just as good as two for the first ~3 months? Even you said earlier that 1 shot is only 50% effective as 2 shots. If protection is so important, it’d seem that intentionally holding back the best protection would defeat the purpose of going all-in on emergency use in the first place.
I think we all agree about this.
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For once, I might be able to clarify something instead of further blurring it.
@meed18, I’ve edited the lower right quadrant of your chart to include a point that I think @glitch99 is making. Since I have no horse in this race, I am probably as objective, and possibly, sadly, obtuse as anyone.
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